Visual acuity is the relative ability of the eye to resolve detail that is usually expressed as the reciprocal of the minimum angular separation in minutes of two lines just resolvable as separate and that forms in the average human eye an angle of one minute.

Visibly Inc. has developed a method for determining a patient's visual acuity electronically via a web-based software system that can be self-administered wherever convenient. This method provides an efficient alternative for people to have immediate access to visual acuity measurements.

The Visibly Digital Acuity Product (VDAP) is a web-based, self-guided software application intended for use by adults, ages 22 to 40, at home, to evaluate visual acuity with or without correction. The standalone software application allows the user to interface with the software via a web browser on two internet-enabled devices:

• A computer screen (the Display) which displays optotypes
• A touchscreen mobile device (the Remote) which operates as a remote control and interface for the user to respond to prompts related to the optotypes appearing on the Display while standing 10 feet away

The software allows users to view and respond to displayed optotypes and uses the responses to categorize a user's visual acuity into one of two buckets:

• 20/25 or better
• Worse than 20/25

Inclusion Criteria:

• 1. Be between 22 and 40 years (inclusive) of age at the time of consent 2. Be able and willing to provide written informed consent, attend all scheduled visits and comply with all study procedures

Exclusion Criteria:

• 1. Have any of the following conditions (based on subject report):

  1. Advanced eye disease in either eye;
  2. Poor vision as a result of refractive surgery in either eye;
  3. Unable to walk;
  4. Unable to hear or follow audio instructions.